Ice making apparatus



J. W. BRASWELL, JR

ICE MAKING APPARATUS Sept. 20, 1955 2 Sheets-Sheet 1 Filed July 25, 1952INVENTOR I J \MBrasweN'J ATTORNEY Sept. 20, 1955 J. w. BRASWELL, JR

ICE MAKING APPARATUS 2 Sheets-Sheet 2 Filed July 25, 1952 J? W- Braswlf, Jx

' dbmw ATTORNEY United States Parent 2,718,123 icE MAKING APPARATUSJames W. Braswell, Jr., Midway Park, N. c. Application July 25, 1952,Serial'No. 300,923

Claims. c1. '62-106) My invention relates to a machine for making ice.

An important object of the invention is to provide a machine for makingseparate ice units in a'water mass, the ice units separating from thefreezing means by partial melting, and then floating to the top of thewater mass for harvesting.

A further object of the invention is to provide a machine of theabove-mentioned character, having the combined freezing and meltingelements arranged exteriorly of the watertank and contacting therewithat spaced intervals.

A further object of the invention is to provide means for alternatelysupplying a cold liquid refrigerant and a hot liquid refrigerant to thetubular elements for forming the ice units within the tank and partlymelting the ice units to free them from the side wall of the tank.

A further object is to provide. means wherein the expansion orvaporization of the liquid refrigerant occurs exteriorly of the freezingand melting elements, for forming the cold liquid refrigerant and thegaseous refrigerant to be supplied to the compressor for producing thehot liquid refrigerant.

A further object is to provide in an ice making machine of theabove-mentioned character a novel pressure regulating device used toestablish a required pressure differential between the hot and coldliquids of the system, and compensating for variable conditions of thecompressor.

A further object is to provide in a machine of the abovementionedcharacter means for controlling the shape and size of the ice particles.

A further object is to provide in a machine of the abovementionedcharacter automatic valve means for maintaining the necessary volume ofliquid refrigerant within the system at all times.

A still further object of the invention is to provide a machine of theabove-mentioned character which is highly simplified in construction,reliable and efiicient in operation and entirely automatic.

Other objects and advantages of the invention will bev apparent duringthe course of the following description.

In the accompanying drawings, forming a part of this application, and inwhich like numerals are employed to designate like parts, throughout thesame,

Figure l is a central vertical section, partly diagrammatic, through anice making machine embodying my invention, parts in elevation, I v

Figure 2 is a horizontal cross section taken substantially on line 2-2of Figure l,

Figure 3 is an enlarged central vertical section through a surge tankand refrigerant float valve, parts broken away,

Figure 4 is a similar section through a pressure regulating device ofthe machine,

Figure 5 is a similar section through a master valve, Figure 6 is ahorizontal cross section on line 66 of Figure 5, Y

Figure 7 is an enlarged fragmentary side elevation of a 2,718,123Patented Sept. 20, 1955 "ice valve disc in the master valve and showingan elongated port formed therein, and

Figure 8 is an enlarged vertical section through a header of the machineand showing a ball check valve arranged therein, parts in elevation.

In the drawings, Where for the purpose of illustration is shown apreferred embodiment of my invention, the numeral 10 designates avertical tank or casing closed at its bottom and having an upper taperedend portion 11. The tank 10 holds water to be frozen in producing iceparticles and the level of the water in the tank is indicated at L,Figure 1. The ice units or particles 12 formed by the machine are frozenupon the inner face of the tank 10, and when melted therefrom arereleased and float upwardly to the level L. At the surface, the iceparticles 12 are scooped up by a horizontal conveyor 13 and fedlengthwise through the conveyor. The conveyor is driven by a motor andmay be substantially the construction shown in my Patent Number2,590,499.

The level of the water in the tank 10 is maintained constant byv a floatoperated valve 14, receiving water under pressure from a pipe 15. Whenthe valve 14 opens to supply additional water to the tank 10, this wateris discharged through a pipe 16. When the level of the water is re-'stored to normal, the valve 14 automatically closes. The pipe 16 extendsabove the conveyor 13 so that the incoming water is sprayed over therotary conveyor. 'By thus spraying the incoming water, it is freed ofair, and by so doing, prevents the formation of white ice particles. Asshown in Figure l; the ice particles 12 may be circular discs of icewhich are formed upon the inner surface of the tank 10 as previouslystated, and as will be more fully described hereinafter.

Surrounding the vertical tank 10 are circumferentially spaced combinedfreezing and melting tubular elements 17. The elements 17 extendvertically, and are bent at intervals throughout the major portion oftheir lengths for providing inner U-shaped contacting portions18 whichcontact the outer surface of the tank 10 at vertically spaced points 19.The elements 17 may be soldered or otherwise secured to the tank. 10,and the elements 17 are preferably thirty in number, as indicated.

Each vertical tubular element 17 is provided at its top with a reducedpipe 20, having a small bore to serve as a liquid refrigerant restrictorport. The reduced pipes 20 are connected with and discharge into anenlarged annular header or pipe 21. When the liquid refrigerant, cold orhot, passes through the reduced pipes 20 having this header functions asan evaporator, and the liquid refrigerant is partly converted into agas, and the expanding gas extracts heat from the remaining liquidrefrigerant which has its temperature reduced in the header 21 toapproximately 10 degrees F.

Arranged exteriorly of and near the tank 1%) is a vertical surge tank 22having its bottom and top ends closed. A pipe 23 leads into the top ofthe surge tank 22 and into the evaporator header 21. The pipe 23 has arelatively large diameter, as compared to the elements 17. Also leadinginto the top of the surge tank 22 is a pipe 24 of relatively largediameter, leading to the intake side of a compressor 25. When the liquidrefrigerant, cold or hot, passes through the restrictor pipes 20 andenters the evaporator header 21, the liquid refrigerant vaporizes inpart, as stated, and the vaporizing refrigfrigerant passes upwardlythrough the pipe 24 and is sup plied to the intake side of thecompressor 25.

Connected with the outlet side of the compressor 25 is a condenser coil26, receiving hot compressed refrigerant vapor from the compressor,which is converted into liquid while passing through the condenser coil26, before discharging into a receiver tank 27. The liquid refrigerantwithin the tank 27 is hot and has a temperature of approximately 110.degrees F. An outlet pipe 23 is connected with the receiver tank 27 andleads to a master valve 29, This master valve includes a vertical casing30, having a top 31, Figure 5, provided with a tapered portion 32. Ahorizontal tapered valve disc 33 slidabl'y engages the tapered portion32 and has a circumferentially elongated opening or slot 34 formedtherein which extends through the top and bottom edges of the same, asshown in Figures 5 and 7. The valve disc 33 is rigsecured to a verticalshaft 35, mounted in a fixed bearing 36, and carrying a worm wheel 37.The shaft 35 is urged upwardly by a compressible coil spring 38 whichserves to hold the valve disc 33 in sliding contact with the taperedportion 32. The worm wheel 37 is driven by a worm' 39, Figure 6, formedupon a horizontal shaft 40, carrying a second worm wheel 41, driven by aworm 42, carried by a vertical shaft 43 The shaft 43 is driven by amotor 44. The casing 3.3 may be partially filled with oil, which alsoenters the casing sec: tion 45, enclosing the gearing including theelements 42 and 43. The oil and air in the casing sections 30 and. 4.5form'a seal between the motor 44 and the hot aiquid refrigerant enteringthe master valve 29 from the pipe 28. This arrangement prevents therefrigerant from causing any damage to the copper parts of the motor 44.

Arranged beneath the tank 10 is an annular horizontal tubular header 46,connected with a radial pipe 47, connected with the outlet side of arotary pump 48, the intake side of which is connected with a pipe 49,leading to the lower end of the surge tank 22, which holds the coldliquid refrigerant. The hot liquid refrigerant is supplied to the lowerend of each tubular element 17 through a pipe 50, and this pipe leadsinto a tubular header 51, connected with the lower end of the tubularelement 17. The header 51 has a valve seat 52 adjacent to the pipe 50,and an inverted V-shaped deflector 53 is arranged upon one side of thevalve seat. The element 54 is a ball check valve to engage the valveseat 52. Cold liquid refrigerant is supplied to the lower end of eachtubular element 17 through a pipe 55, connected with the annular header46 and the lower end of the particular tubular header 51. The tubularheader 51 has a second valve seat 56 adjacent to. the pipe 55, Fig ure8.

The ball check valve 54, is adapted to alternately engage the valveseats, 52 and 56. When the hot liquid refrigerant is being supplied fromthe master valve 29; to the lower end of one tubular element 17, theincoming hot liquid refrigerant, being at a higher pressure than thecold liquid refrigerant, unseats the ball check valve 54 which is thrownover the deflector 5 3 an engages the valve seat 56, thus preventing thehot liquid refrigerant from entering the pipe 55.. When the freezingcycle is occurring and the supply of hot liquid is cut oi by the valvedisc 33, cold'liquid refrigerant passes through the pipe 55 and unseatsthe ball check valve 54, from the seat 56 and causes it to engage theseat 52, thus preventing the cold liquid refrigerant from entering thepipe 50.

Connected in the pipe 47 is a pressure regulating device or valve 57,having a valve element 58 which is regulated by a reciprocatory stem59., secured to a flexe. di phr 0 i h e asin e o 61- A, ube 62 leadsfrom the pipe-28 into the casing section 61 above the diaphragm 60, asshown, The pressure regulating valve 57 has an intermediate tubularcasing section, 63 surrounding the stem 59 and spaced therefrom to, forma, passage 62', leading into, the casing section 61 below the diaphragm60. The passage 62 also leads into. a

lower casing section 63 of the pressure regulating valve,

within which the valve elements 58 operate.

The pressure of the hot liquid from the tube 62 acts upon the top of thediaphragm 60, and tends to force the valve element 58 open, which allowsmore cold liquid from the pipe 47 to flow through the valve 58 and intothe header 46. This elevates the pressure in the header 46, and thispressure acts against the bottom of the diaphragm 60, tending to causethe valve element 58 to throttle or close. This throttling actioneffects a predetermined pressure dilferential between the hot and coldliquid refrigerant flowing in the system. This is necessary because thehot liquid pressure must be slightly higher than the cold liquidpressure, so that it can force its way into the header 51 against thepressure of the cold liquid refrigerant. The pressure of the hot liquidwill vary with the conditions under which the system must operate.Weather temperature, condenser water temperature, etc., will affect theoperating pressures of the machine, and the valve device 57 maintainsthe proper differential in pressure between the hot and cold liquid inthe system. The cold liquid from the casing section 63' passes throughthe passage 62, in order to reach the bottom of the diaphragm 60.

A float controlled valve 64 is mounted upon the side of the surge tank22, and embodies a float 65. Should the level of the cold liquidrefrigerant in they surge tank fall below the selected level, the float65 will open the valve and hot liquid refrigerant will be supplied tothe tank 22 through a pipe 66, connected with the pipe 28.

A valve 67 is connected inthe pipe 28 and is held open by a solenoid 68when the solenoid is energized. The solenoid 68 is connected with wires69 and 70, as shown. Contacts 71, Figure 3, are connected in the wire70, and when the level of the cold liquid refrigerant in the tank 22rises above a selected point, the float 65 breaks the electricalconnection between the contacts 71, and the solenoid 68 is deenergized,and the valve 67 closes.

The operation of the machine is as follows:

The freezing cycle of the machine takes place simultaneously in all ofthe tubular elements 17 except one, which is simultaneously defrosted bythe action of the hot liquid refrigerant. Considering the freezingcycle, the cold liquid refrigerant passes from the header 46 through thepipes 55 and unseats the ball check valves 54 which will now engage thevalve seats 52. The cold liquid refrigerant will now pass upwardlythrough all of the tubular elements 17 except the single element whichis being defrosted. The cold liquid refrigerant has a temperature ofabout 10 degrees F., as previously stated, Since the portions 18 of theelements 17' are in thermal contact with the outer face of the tank 10,the ice particles or discs 12 will form upon the inner face of the tank10 at the points 19, and surrounding the same. The surface of the innerface of the tank where the ice is formed remains relatively free ofcorrosion while the remainder of the surface corrodes to a certainextent and gathers foreign matter from the water. This corrosive actionincreases the heat insulating properties of the side wall of the tankand confines the non-corroded areas of the tank adjacent to the points19, thereby limiting the size of the circular ice discs 12 formed by themachine. The ice discs 12 are thus maintained separate, and will notcontact and freeze together into an integral mass, but will readilyseparate individually from the tank and float to the surface L, whenpartially melted by the defrosting of the individual elements 17.

While twenty-nine of the elements 17 are receiving the cold liquidrefrigerant, and causing the formation of the ice. particles 12, one ofthe elements 17 is receiving hot liquid refrigerant and being defrostedthereby for releasing the adjacent ice particles 12 from the tank, sothat they may float to hesurfaee L andxbe harvested. The defrostingcycle is regulated by the valve disc 33 which is turning very slowly, inorder to provide a suitable time interval for any particular element 17.The speed of rotation of the valve disc 33 is preferabiy about fourrevolutions per hour.

When the single elongated port 34 of the valve disc 33 moves intoregistration with one pipe 50, the hot liquid refrigerant from themaster valve 29 now passes through the particular pipe 50 and enters theparticular header 51. The hot liquid refrigerant unseats the ball checkvalve 54, which is now transferred to the seat 56. The hot liquidrefrigerant is under higher pressure than the cold liquid refrigerant,as controlled by thepressure regulator 57, so that the ball check valve54 will remain seated upon the seat 56 during the defrosting cycle,which is defined by the circumferential length of the port 34, and speedof rotation of the valve disc 33. The hot liquid refrigerant flowingthrough the tubular element 17 heats the tank adjacent to the iceparticles 12, and sufficiently melts the ice particles to free them fromthe side wall of the tank It The heated refrigerant of course forces thecold liquid refrigerant from the tubular element 17, and the cold andhot liquid refrigerant both discharge through the restrictor pipe 20into the evaporator header 21. At the end of the defrosting cycle forthe particular element 17, the port 34 moves out of registration withthe particular pipe 50 and the cold liquid refrigerant is again suppliedthrough the pipe 55 to the particular header 51 and tubular element 17,so that the freezing cycle may again start. The port 34 then movesintoregistration with another of the pipes 50, so that the defrosting cyclemay take place in another of the tubular elements 17, while the freezingcycle continues in the other twenty-nine elements 17.

The cold and hot liquid refrigerant discharging from the severalelements 17 through the restrictor pipes 20, enters the annularevaporator header 21, where its pressure is reduced, and a portion ofthe liquid refrigerant vaporizes in the header 21, and this reduces thetemperature of the remaining liquid refrigerant to approximately 10degrees F. This cold liquid refrigerant is discharged downwardly intothe surge tank 22, while the vaporized refrigerant passes through thepipe 24 to the compressor 25. The compressed refrigerant discharges intothe condenser 26 and the hot liquid refrigerant is held in the receivertank 27. The hot liquid refrigerant is supplied from the tank 27 to themaster valve 29, by way of the pipe 28.

It is to be understood that the form of my invention herewith shown anddescribed is to be taken as a preferred example of the same, and thatvarious changes in the shape, size and arrangements of parts may beresorted to, without departing from the spirit of the invention or scopeof the subjoine'd claims.

Having thus described my invention, I claim:

1. An ice making machine comprising a tank for holding water, aplurality of tubular elements arranged exteriorly of the tank and formedto contact the outer surface of the tank at a plurality of spacedpoints, means connected with corresponding ends of the tubular elementsfor alternately introducingcold and hot liquid refrigerant into thetubular elements and causing the liquid refrigerant to pass through theelements, restrictor pipes connected with the other corresponding endsof the tubular elements and having reduced restrictor bores receivingthe liquid refrigerant from the tubular elements, and evaporator meansincluding a common evaporator header connected with the restrictor pipesand having a relatively large bore for receiving the refrigerant fromthe restrictor pipes and effecting a partial vaporization of the same.

2. A machine for making ice comprising a tank adapted to hold water,automatic valve means connected with the tank for spraying water intothe top of the tank and maintaining a substantially constant level ofwater near the top of the tank, a rotary conveyor element mounted uponthe tank near the level of the water and adapted to harvest iceparticles Which are formed within the tank and float to the top thereof,a plurality of tubular elements arranged exteriorly of the tank andbeing in thermal contact with the outer face of the tank at spacedpoints and adapted to receive a refrigerant, means connected with 5;;the tubular elements for alternately introducing cold and hot liquidrefrigerant into the same, and evaporator means connected with thetubular elements and receiving the liquid refrigerant therefrom andpartially vaporizing the same.

3. An ice making machine comprising a tank for bolding water, aplurality of tubular elements arranged exteriorly of the tank andcontacting the outer surface of the tank at a plurality of spacedintervals, evaporator means connected with corresponding ends of thetubular elements for receiving a liquid refrigerant therefrom andeffecting partial vaporization of the liquid refrigerant, a surge tankconnected with said evaporator means and receiving liquid and vaporizedrefrigerant therefrom, means connected with the surge tank for receivingthe vaporized refrigerant therefrom and compressing the same andsubsequently condensing the vaporized refrigerant to form hot liquidrefrigerant, headers connected with the other corresponding ends of thetubular elements and having two-way check valves for permitting hot orcold liquid refrigerant to enter the headers and tubular elements,conduit means connecting the surge tank and headers for conveying coldliquid refrigerant from the surge tank to the headers when the two waycheck valves of the headers are in one position, and separate conduitmeans connecting the headers and said means connected with the surgetank for conducting hot liquid refrigerant to the headers when the twoway check valves are in the other position.

4. An ice making machine comprising a tank for holding water, aplurality of tubular elements arranged ex- 3 teriorly of the tank andcontacting the outer surface of the tank at a plurality of spacedintervals, evaporator means connected with corresponding ends of thetubular elements and receiving liquid refrigerant therefrom andeffecting partial vaporization of the liquid refrigerant, a

r surge tank connected with said evaporator means and receiving liquidand vaporized refrigerant therefrom, a

compressor connected with the surge tank and receiving the vaporizedrefrigerant therefrom and compressing the same, condenser meansconnected with the compressor 4 gpand receiving the compressed vaporizedrefrigerant therefrom and condensing the same to form hot liquidrefrigerant, headers connected with the other corresponding ends of thetubular elements and having two Way check valves for permitting hot orcold liquid refrigerant to 5Q 6nlr the headers and tubular elements,conduit means connecting the surge tank and headers for conducting coldliquid refrigerant from the surge tank to the headers when the two waycheck valves of the headers are in one position, and a master valveconnected with said condenser means and with all of said headers andreceiving hot liquid refrigerant from the condenser means, the mastervalve including a movable metering part arranged to permit passage ofthe hot liquid refrigerant into one header only when the two way checkvalve of such header .;is in the other position and while the otherheaders are receiving cold liquid refrigerant from said conduit means.

5. An ice making machine comprising a tank for holding water, aplurality of tubular freezing elements arranged exteriorly of the tankand contacting the outer surface of the tank, evaporator means connectedwith corresponding ends of the tubular freezing elements and receivingliquid refrigerant therefrom and effecting partial vaporization of theliquid refrigerant, a surge tank connected with said evaporator meansand receiving liquid ,and vaporized refrigerant therefrom, a compressorconnected with the surge tank and receiving the vaporized refrigeranttherefrom and compressing the same, condenser means connected with thecompressor and receiving compressed vaporized refrigerant therefrom andcondensing the same to form hot liquid refrigerant, headers connectedwith the other corresponding ends of the tubular freezer elements andhaving two way check valves permitting hot or cold liquid refrigerant toenter the headers and tubular freezing elements, conduit meansconnecting the surge tank and headers for conducting cold liquidrefrigerant from the surge tank to the headers when the two way checkvalves of the headers are in one position, a pump connected in saidconduit means to propel the cold liquid refrigerant therethrough, amaster valve including a rotary metering part having port, a pipeconnecting the master valve with said condenser means and conducting hotliquid refrigerant to the master valve, a plurality of pipes connectingthe master valve and headers and adapted to alternately register withthe port of the rotary metering part, whereby hot liquid refrigerant isintroduced into one of said headers while the other headers arereceiving cold liquid refrigerant from the conduit means, and a pressureregulating device connected with the conduit means and said pipeconnecting the master valve and condenser means and maintaining apressure differential between the hot and cold liquid refrigerant.

6. An ice making machine comprising a tank to hold water, a plurality oftubular freezer elements arranged exteriorly of the tank and contactingthe outer surface thereof, evaporator means connected with the tubularfreezer elements and receiving liquid refrigerant therefrom andpartially vaporizing the refrigerant, a surge tank connected with saidevaporator means and receiving liquid and vaporized refrigeranttherefrom, the liquid refrigerant passing to the bottom of the surgetank and the vaporized refrigerant accumulating in the upper portion ofthe surge tank, a compressor connected with the upper portion of thesurge tank and receiving the vaporized refrigerant therefrom andcompressing the same, condenser means connected with the compressor andreceiving the compressed vaporized refrigerant therefrom and condensingthe same to form hot liquid refrigerant, valve devices connected withthe tubular freezer elements for permitting hot or cold liquidrefrigerant to enter the same, conduit means connected with the surgetank near its lower end connected with the valve devices for conductingcold liquid refrigerant to the same, a master valve including a movablemetering part, having a port, a pipe connecting the master valve andsaid condensor means and conducting hot liquid refrigerant to the mastervalve, a plurality of pipes connecting the master valve and said valvedevices and adapted to register with the port of the movable meteringpart, whereby hot liquid refrigerant is introduced into one ofthetubular freezer elements while the other elements are receiving coldliquid refrigerant from the conduit means, and automatic valve meansconnected with the surge tank and said pipe for causing hot liquidrefrigerant from the pipe to enter the surge tank and maintain aconstant level of liquid refrigerant Within the surge tank.

7. In an ice making machine, a tank to hold water, tubular freezerelements arranged upon the outer surface of the tank and thermallycontacting the outer surface of the tank at spaced intervals, evaporatormeans connected with the tubular freezer elements and receiving liquidrefrigerant therefrom andpartially vaporizing the refrigerant, a surgetank connected with the evaporator means and receiving liquid andvaporized refrigerant therefrom, mechanical refrigeration meansconnected with the surge tank and receiving the vaporized refrigeranttherefrom and compressing and condensing the same to form hot liquidrefrigerant, conduit means connecting the surge tank and tubular freezerelements and conducting cold liquid refrigerant to the elements so thatthey may effect the freezing of ice particles upon the inner surface of'the tank, a master valve connected with the mechanical refrigerationmeans and receiving the hot liquid refrigerant therefrom, and aplurality of pipes connected with the master valve and tubular freezerelements, the master valve including a rotating disc having a singleelongated opening formed therein for alternate registration with saidpipes, whereby the hot liquid refrigerant is conducted to one of saidtubular freezer elements while the other elements are receiving the coldliquid refrigerant.

8. An ice making machine comprising a tank to hold water, a plurality ofelongated tubular elements arranged exteriorly of the tank and formed tocontact the tank at a plurality of spaced points along their lengths,restrictor pipes connected with corresponding ends of the tubularelements for receiving liquid refrigerant therefrom, a substantiallyannular evaporator header connected with restrictor pipes and having arelatively large bore and receiving the liquid refrigerant from therestrictor pipes and effecting partial vaporization of the same, a surgetank connected with the evaporator header and receiving a mixture ofliquid and vaporized refrigerant therefrom, mechanical refrigerationmeans connected with the surge tank and receiving vaporized refrigeranttherefrom and compressing and condensing the vaporized refrigerant toform hot liquid refrigerant, headers having two way check valvesconnected with the other corresponding ends of the tubular elements, asubstantially annular header arranged near said headers and connectedwith the surge tank and receiving cold liquid refrigerant therefrom,pipes connecting the last named annular header with said headers forconducting cold liquid refrigerant thereto, a master valve connectedwith the mechanical refrigeration means and receiving hot liquidrefrigerant therefrom, and pipes connected with the master valve andwith said headers for conveying the hot liquid refrigerant thereto.

9. An ice making machine comprising a tank for holding water, aplurality of tubular elements arranged adjacent to a wall of the tankand being in thermal contact with the wall of the tank, means connectedwith corresponding ends of the tubular elements for alternatelyintroducing cold and hot liquid refrigerant into the tubular elementsand causing the liquid refrigerant to pass through said elements,restrictor devices connected with the other corresponding ends of thetubular elements and receiving the liquid refrigerant from the tubularelements, and evaporator means connected with the restrictor devices andreceiving the refrigerant from the restrictor devices and effectingpartial vaporization of the same.

10. An ice making machine comprising a tank for holding water, aplurality of tubular elements arranged adjacent to a wall of the tankand being in thermal contact with said wall, means connected withcorresponding ends of the tubular elements for alternately introducingcold and hot liquid refrigerant into the tubular elements and causingthe liquid refrigerant to pass through said elements, restrictor pipesconnected with the other corresponding ends of the tubular elements andhaving reduced restrictor bores receiving the liquid refrigerant fromthe tubular elements, and a common evaporator header connected with therestrictor pipes and receiving the refrigerant from the restrictor pipesand effecting partial vaporization of the same.

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